Explanation

steel made by adding enough strong deoxidizer (such as silicon, aluminum, etc.) to the molten steel before pouring. This kind of steel is well deoxidation and does not produce CO gas when solidified in the ingot mold. Therefore, the molten steel remains calm without boiling. The added deoxidizer preferentially combines with the oxidation in the steel liquid to generate oxides -- silicon dioxide and aluminum oxide. Most of the oxides enter slag, and some of them remain in steel, becoming non-metallic inclusions. A considerable shrinkage hole can be formed in the center of the ingot. After forging and rolling, the cutting amount is large, and the yield rate is low, sometimes even lower than 50% (such as large forgings with strict quality requirements). The purity of killed steel is high, the chemical composition segregation is small, and the mechanical properties are relatively uniform and stable in all parts of the ingot, especially the initial impact and cold stamping properties are good. It can be used as steel for forging, carburizing and heat treatment. Almost all carbon steel and alloy steel with a carbon content of approximately 0.25% or more are. killed steel steel designation is not marked.

Classification